Absolutely, Puyol made no attempt to play the ball and just blundered into the back of him, no doubt it was a penalty. The red card was a tad harsh but those are FIFA's rules, he denied a goalscoring chance and had to go.
It's not a rule that i'm a fan of, but if they take away the red card aspect then it'll mean defenders deliberately fouling and taking the 50-50 penalty instead of the guaranteed goal, and i have no doubt that it'll happen often.
Actually he didn't even bundle into him, it was Fabregas's swinging leg got caught up in Puyol's legs, it was accidental, I really don't think it should have counted as a red card because there was zero intent, but it might save our bacon in the second leg. There are soo many times Arsenal have been screwed by awful decisions so, screw it, we get one go our way.
I wouldn't give Walcott too much credit, when you see the replays you see it rather scuffed his shot(as per usual), no real power and quite probably Valdes should have done much better and apart from his scuffed shot, ran the ball a lot mostly to pass 10 yards back.
However, against a team like Barca its better to run up the wing and push them back, than sit in your own half being way too defensive. IF Theo's final ball wasn't great after his goal, I don't know what Sagna's was, his passing and crossing was truly awful. Since the end of the first season when he got injured, damn, its been downhill since the day he came back, he wasn't great then, he's ruddy awful right now. He'd become a fairly poor right back by the end of last season, making massive mistakes for at least 2 of those 4 goals against Liverpool, and against Chelsea this year he was pathetic, offensive he offers so little(except that one game recently).
I really don't know what happened, freak first year form, career changing injury, or just can't get back to form for whatever reason. Hopefully he can get back to his first years form but we're now at the point where 3 years on he's had two bad seasons and one great season and its getting close to calling time on him and getting a replacement in. Frankly I'm way more than happy to get a right winger/right back type player who can be back up to Eboue and Nasri/Arshavin/Rosicky. Cash in on Sagna while some people still think he's worth a bit of cash I think.